The present invention relates to a disk array apparatus in which it is possible to utilize a plurality of kinds of storage devices, and to a control method for control of the disk array apparatus.
A disk array apparatus is constructed on the basis of, for example, the use of RAID (Redundant Array of Independent Inexpensive Disks), in which a multiplicity of disk drives are disposed in an array. Each of the disk drives has a physical storage area; and, logical volumes (logical devices), which constitute logical storage areas, are formed on the physical storage area. A host computer is capable of reading and writing desired data from and to the disk array apparatus by issuing a write command or a read command having a predetermined format to the disk array apparatus.
One known example of a technique for exerting access control on data stored in the disk array apparatus is embodied in a disk control method described in a patent publication (JP-A-2000-112822). This method sets any one of three kinds of access attributes, including “read and write enable”, “write disable” and “read and write disable”, for each logical device in a RAID system. In addition, this method changes the response and processing as to various commands sent from a host computer in accordance with access attributes set for individual logical devices.
Independently of demands for access control on logical devices, there are increasing market demands for long-term saving of data stored in logical devices. For example, organizations, such as enterprises and government and municipal offices, manage various kinds and large quantities of data, such as electronic mail data, contract data and document data. Some of these kinds of data need to be saved for a predetermined period by law or company policy. Although the period of obligatory saving differs for the kinds of data, certain kinds of data must be saved for a period of several to ten and several years (or far more years).
For this reason, a system manager archives and manages data that must be saved for a long term. At the request of an audit organization or the like, the system manager searches for and accesses the corresponding long-term saved data from a disk array apparatus and provides the requested data to the audit organization or the like. Accordingly, if various kinds and large quantities of data are to be saved for a long term, the system manager needs to manage the storage areas of individual data and the like, and must perform time-consuming work for management, operation and maintenance of long-term saved data.